The present disclosure is related to wellbore operations and, in particular, to an improved tension member or slickline used in wellbore intervention operations.
Hydrocarbons are typically produced from wellbores drilled from the Earth's surface through a variety of producing and non-producing subterranean zones. The wellbore may be drilled substantially vertically or may be drilled as an offset well that has some amount of horizontal displacement from the surface entry point. A variety of servicing operations may be performed in the wellbore after it has been drilled and completed by lowering different kinds of downhole tools into the wellbore. For example, measuring instruments are commonly lowered into the wellbore to obtain various downhole measurements, such as bottom hole pressure and temperature. Various sampling devices are also commonly lowered into the wellbore to obtain fluid samples at various target zones of the subterranean formation in order to determine the exact composition of the formation fluids of interest.
Such servicing operations are typically undertaken by lowering the downhole tool into the wellbore on a tension member conveyance, such as a slickline. Slickline is a thin, non-electric cable or tension member usually made up of a single strand of metal wire. The single round strand of wire typically passes through a stuffing box and pressure-control equipment mounted on a wellhead to enable slickline operations to be conducted safely on live wellbores. After the wellbore servicing operation is completed, the downhole tool is withdrawn from the wellbore and the slickline is re-coiled back onto an adjacent wire spool or drum. In some production sites, wellbores may be very deep, for example extending more than 10,000 feet below the surface. With progressing technology, wells are getting even deeper and demands to service such deeper wells with slickline are correspondingly increasing.
Currently, slickline wellbore intervention is principally limited to metallic tension members to convey and retrieve the downhole tools between the surface and target zones of the wellbore. While such metallic tension members have been optimized over the years and are quite efficient for this service, they are rapidly reaching mechanical operating limits due to the increasing depths of drilled wellbores. With increasing wellbore depths, the weight of the metallic tension member as experienced at the surface limits the maximum run-in-hole working depth. Metallic tension members are also limited by material fatigue limits over time after being repeatedly introduced and retracted into/from the wellbore. In some servicing operations, for example, the tension member is repeatedly reciprocated within the wellbore over a short distance to create impact loads designed to carry out various mechanical procedures downhole. Such repeated stresses placed on the tension member can eventually result in the tension member reaching its fatigue limit. Accordingly, it may prove advantageous to have more robust and lightweight tension members for use in slickline wellbore intervention operations.